There is definitly a problem with the destination folder path.
Your above error message says, it wants to put the contents to a file in the directory /files/grantapps/
, which would be beyond your vhost
, but somewhere in the system (see the leading absolute slash )
You should double check:
/home/username/public_html/files/grantapps/
really present./home/username/public_html/files/grantapps/